save project as an minimal example

Author: cherkavi

android/android-minimal-stable-app/.gitignore

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+build
+.gradle
+gradle/
+gradlew
+gradlew.bat

android/android-minimal-stable-app/README.md

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+# App for sending curl requests to localhost
+## preparations
+### java JDK
+```sh
+# switch to java 17 (`sdk install java 17.0.17-zulu`)
+java -version
+```
+### android command line tools
+```sh
+mkdir /home/soft/android_sdk
+pushd /home/soft/android_sdk
+curl --silent https://developer.android.com/studio | grep commandlinetools-linux | grep href
+wget https://dl.google.com/android/repository/commandlinetools-linux-13114758_latest.zip
+unzip commandlinetools-linux-*.zip
+```
+```sh
+pushd /home/soft/android_sdk
+# accept all licenses,         the root should be the same as in local.properties
+./cmdline-tools/bin/sdkmanager --sdk_root=/home/soft/android_sdk --licenses
+```
+```sh
+pushd /home/soft/android_sdk
+./cmdline-tools/bin/sdkmanager --sdk_root=/home/soft/android_sdk --install "platform-tools" "platforms;android-34" "build-tools;34.0.0"
+# check with app/build.gradle `android { compileSdk 34
+```
+
+### android vs gradle
+> Android Gradle Plugin 8.2.2 is not compatible with Gradle 9.x 
+```sh
+gradle wrapper --gradle-version 8.3 --distribution-type all
+./gradlew --version
+```
+
+## build
+```sh
+rm -rf build .gradle app/build app/.gradle
+gradle --stop
+gradle --status
+./gradlew --stop
+./gradlew --status
+
+./gradlew clean :app:assembleDebug --no-build-cache
+ls -la app/build/outputs/apk/debug/app-debug.apk
+```
+
+## install application on physical android device
+```sh
+adb devices
+# if no devices: https://github.com/cherkavi/cheat-sheet/blob/master/android-cheat-sheet.md#adb
+adb install -r app/build/outputs/apk/debug/app-debug.apk
+```

android/android-minimal-stable-app/app/build.gradle

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+apply plugin: 'com.android.application'
+
+android {
+    namespace 'com.example.buttonapp'
+    compileSdk 34
+    defaultConfig {
+        applicationId "com.example.buttonapp"
+        minSdk 24
+        targetSdk 34
+    }
+}
+
+dependencies {
+    implementation 'androidx.appcompat:appcompat:1.6.1'
+    implementation 'com.squareup.okhttp3:okhttp:4.12.0'
+}

android/android-minimal-stable-app/app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <uses-permission android:name="android.permission.INTERNET" />
+
+    <application
+        android:allowBackup="true"
+        android:label="Button App"
+        android:usesCleartextTraffic="true"
+        android:theme="@style/Theme.AppCompat.Light.DarkActionBar">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

android/android-minimal-stable-app/app/src/main/java/com/example/buttonapp/MainActivity.java

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+package com.example.buttonapp;
+
+import android.os.Bundle;
+import android.widget.Button;
+import android.widget.Toast;
+import androidx.appcompat.app.AppCompatActivity;
+import java.io.IOException;
+import okhttp3.Call;
+import okhttp3.Callback;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.Response;
+
+public class MainActivity extends AppCompatActivity {
+
+    private final OkHttpClient client = new OkHttpClient();
+    // 10.0.2.2 is how the Android Emulator sees your computer's localhost
+    private final String SERVER_URL = "http://10.0.2.2:8080/";
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+
+        Button btnOne = findViewById(R.id.btn_one);
+        Button btnTwo = findViewById(R.id.btn_two);
+
+        btnOne.setOnClickListener(v -> makeRequest("button1"));
+        btnTwo.setOnClickListener(v -> makeRequest("button2"));
+    }
+
+    private void makeRequest(String path) {
+        Request request = new Request.Builder()
+                .url(SERVER_URL + path)
+                .build();
+
+        client.newCall(request).enqueue(new Callback() {
+            @Override
+            public void onFailure(Call call, IOException e) {
+                runOnUiThread(() -> 
+                    Toast.makeText(MainActivity.this, "Network Error: " + e.getMessage(), Toast.LENGTH_LONG).show());
+            }
+
+            @Override
+            public void onResponse(Call call, Response response) throws IOException {
+                final String responseData = response.isSuccessful() ? "Success!" : "Server Error: " + response.code();
+                runOnUiThread(() -> 
+                    Toast.makeText(MainActivity.this, responseData, Toast.LENGTH_SHORT).show());
+            }
+        });
+    }
+}

android/android-minimal-stable-app/app/src/main/res/layout/activity_main.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:gravity="center"
+    android:padding="20dp">
+
+    <Button
+        android:id="@+id/btn_one"
+        android:layout_width="match_parent"
+        android:layout_height="60dp"
+        android:text="Send to /button1"
+        android:backgroundTint="#2196F3"/>
+
+    <Button
+        android:id="@+id/btn_two"
+        android:layout_width="match_parent"
+        android:layout_height="60dp"
+        android:layout_marginTop="20dp"
+        android:text="Send to /button2"
+        android:backgroundTint="#4CAF50"/>
+
+</LinearLayout>

android/android-minimal-stable-app/build.gradle

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+buildscript {
+    repositories {
+        google()
+        mavenCentral()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:8.2.2'
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}

android/android-minimal-stable-app/gradle.properties

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+android.useAndroidX=true
+android.enableJetifier=true

android/android-minimal-stable-app/local.properties

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+sdk.dir=/home/soft/android_sdk

android/android-minimal-stable-app/settings.gradle

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+rootProject.name = "MyButtonApp"
+include ':app'